Process of making hollow rubber articles.



PATENTED JUNE '7, 1904.

I. F. KEPLER. PROCESS OF MAKING HOLLOW RUBBER ARTICLES.

APPLIOATION FILED MAR.19. 1903.

N0 MODEL.

FIGJZ ATTORNEY Patented June 7, 1904.

UNITED STATES PATENT OEEIcE.

IRVVIN-FLOYD KEPLER, OF AKRON, OHIO, ASSIGNOR TO THE B. F. GOOD- RIOHCOMPANY, OEOHIO, OF AKRON, OHIO, A CORPORATION OF OHIO.

PROCESS OF MAKING HOLLOW RUBBEER ARTICLES.

SPECIFICATION forming" part of Letters Patent No. 762,063, dated June 7,1904.

Application filed March 19, 1903. Serial No. 148.621- (No specimens.)

1?) In whom it may concern;

Be it known that I, IRWIN FLOYD KEPL R, a citizen of the United Statesof America, residing at the city of Akron, county of Summit, and Stateof Ohio, have invented a new and Improved Process of Making HollowRubber Articles, of which the following is a specification. r

This invention relates to an improved proc- I ess of making hollowrubber balls, bulbs, or

other articles, and has for one object to produce a ball, bulb, or otherhollow rubber article having a substantially uniform molecular characterthroughout its'structure.

A further object of the invention is to permit the use of less expensivestock in making hollow rubber articles of equal or greater strength thanthose heretofore produced from higher-grade stock.

A final object of the invention is to provide for making these hollowrubber articles practically without handwork and by simple machineryeasily operated by labor of a less skilled grade and correspondinglymuch less 5 expensive than that required-to run ordinary sheet-rubberealendering-machihes, the use of which is dispensed with in the practiceof my invention.

I attain these objects, primarily, by the use 3 of tubing formed fromuncured rubber stock properly macerated to uniform consistency and,secondarily, by the use of suitable cutting and pressing dies to cut andpress a doublewalled edge-joined blank from such tubing.

In forming a hollow rubber article it has heretofore been the practiceto cut from sheetrubber suitable blanks for the article intended to beproduced, to place these blanks together, first dusting their adjacentfaces with pow- 4 dered soapstone or similar material to preventadhesion, and then to edge-join these blanks by handwork after insertinga capsule of vaporgenerating material or other medium for the productionof gas or vapor during vulcanization, and then to inject air into thearticle so formed by means of a hollow needle with which the blank ispierced and to close the hole made by the needle with gum or cement.This inflation is necessary to produce a bulb that will withstand thetemperature of vulcanization in 5 the vulcani /Jing-mold, since withoutsuch separation the walls will adhere in spite of their pulverulentcoating before the heat reaches a temperature suflicient to liberate thegas from the contained capsule or produce vapor. In my improved articleno piercing of the walls of the blank is necessary, and the necessityfor patching is dispensed with, since the tubing itself contains air,and when a section of it is sheared off by the cutting edges of the diesthe contained air is confined therein, and the walls of the blank arethus distended without additional inflation. The air-bags of uncuredstock thus formed merely by shearing the tubing are further distended bythe immedi- 5 ately following action of the pressing-die, which inuniting the marginal areas tends to confine the air in more limitedspace, and thus increase the distention of the bag, ball, or bulb.

My improved method of making hollow 7 rubber balls, bulbs, or otherarticles involves the cutting or shearing of a double-walled blankconstituting the green or uncured rubber article. from a rubber compoundtube, which preferably has been delivered under pressure from themandrel-dies of an ordinary power tubing-machine. These tube-formingdies assure a practically unform consistency and molecular character andstrength of the pressure-drawn rubber tube, and therefore of the wallsof the green blank cut from said tube. The blank-cutting dies arepreferably so formed that in practically one operation they cut thedouble-walled blank from the die-drawn tubing and compress the edges of3 5 opposite walls of the blank into most intimate 'union, thus leavingthe blank ready to be at once placed in a mold, to the shaping-walls ofwhich the blank is'expanded formatively during the process ofvulcanization by outward 9 pressure of gas or vapor generated from afluid or compound placed within the tubing and preferably prior tocutting the blank from it.

The invention will first be described and then will be particularlydefined in claims hereinafter set forth.

Reference is made to the accompanying drawings. forming part of thisspecification, and in which Figure 1 is a perspective view of apartlyflattened piece of green-rubber tubing which has been deliveredfrom the mandrel-dies of a tubing-machine and with the shape of theblank to be cut from it indicated by dotted lines. Fig. 2 is aperspective view of the den ble-wallcd ed ge-sealned blank as it appearsafter it is cut from the tubing. Figs. 3 and 4 are respectivelytransverse and longitudinal sectional views showing the preferred diesclosed upon the tube as when cutting and edge-seaming the double-walledblank and with the surplus material removed. Fig. 5 is a cross-sectionalview showing the green blank in a vulcanizing-mold prior tovulcanization therein. Fig. 6 is a cross-sectional view showing the bulbas expanded formatively to the mold-walls during'the process ofvulcanization, and Fig. 7 is a longitudinal sectional View of thevulcanized article in the mold.

Ordinary uncured seamless rubber tubing is made from rubber compound orstock which has been properly macerated and mixed and then forcedthrough the mandrel-dies of a tubing-machine. The usual carefulpreparation of the rubber stock and the forcing of it through thetubing-machine dies results almost necessarily in the production of aseamless rubber compound tube having substantially uniform molecularconsistency and strength throughout its entire walls. This structuraluniformity is believed to be greater than that obtained in sheet-rubberstock by passing it through calendcringmachines. The work of thesecalendering-machine operators is skilled labor commanding high wages,while the tubing-machine requires only feeding of the maeerated stockinto a hopper and caring for the die-drawn tubing, which may be done byunskilled and much less expensive labor. By employing rubber tubing asit comes from the tubing-machine instead of using highly-calenderedsheet-rubber stock for making balls, bulbs, or other hollow artieles 1am able to obtain a finished product having walls of great and uniformstrength throughout and at a much reduced 'cost as compared with theusual process of cutting calendered sheet-rubber stock into three ormore segments and then hand-joining these segments and insertingindependently-formed green-rubber plugs or pieces to form or reinforcethe neck or projection of the finished article and then injecting a gasor vapor generating substance to prepare it for the process ofvulcanization. By using my invention the green-rubber ball, bulb, orother hollow article is ready for vulcanization immediately after it iscut and pressed in the form of a double-walled blank from a piece ofuncured tubing made by any suitable hand or power operatedtubing-machine.

In the drawings, Fig. 1 shows a piece of tube 1 cut from a length ofgreen or uncured tubing made by a tubing-machine. This short length oftube 1 is then cut and pressed-by a preferred form of dies (shown inFigs. 3 and 4 of the drawings) into a d ouble-walled blank, having, forexample, the general form shown in Fig. 2 of-the drawings. It will bespeciall y noticed that for quite allthe way around the larger bodyportion of this blank, which later forms the body 2 of the finishedarticle, and also along opposite sides of that projecting portion of theblank which later forms the neck 3 of the bulbous hollow article theedges 4 of the two opposite walls 5 5 of the blank are compressedsufficiently by the diesurfaces to cause them to cohere or to uniteintimately or integrally in a close seam. The opposing die-sections 6 7of preferred form are provided with registering cutting edges 8, usuallycalled the cut-off, which surround the die-concaviti'es 9, which are soshaped that as the cut-off 8 shears the green blank from the tube 1 theedges 4 of the opposing walls 5 of the blank will be pressed intointimate or integral union by and within the die-concavities 9. Thedie-sections have suitable chambers 10 large enough to admit thesemibulbous body of the blank, and there are continuing outwardextensions 11 of the chambers 10 at the blank-neck portion, whichconcavities 11 do not integrally unite the two blank-walls 5 at theinner neck portion of the blank, while the extremity of the blank-neckis joined by the shearing action of the cut-off 8 sufficiently to closeit and to confine within the blank any suitable capsule 12, ofammoniacal fluid or other substance, which will upon the application ofthe temperature requisite for vulcanization generate necessary gas orvapor under sufficient outward pressure to inflate the blank to theshaping-walls of asuitable mold as the blank is being vulcanizedtherein. I may easily inject'the gas or vapor generating substance intothe double-walled edge-seamed blank at the end of its neck portion by ahollow needle instead of placing said substance within the tube prior tocutting the blank therefrom, as I now prefer to do. A marginal opening13, formed by opposing concavities of the diesections outside of thecut-off 8, permits clearance or escape of the waste edgings severed fromit by the cut-off. I may use dies adapted first to cut out and thenedge-compress the double-walled blank in two operations; but I prefer touse suitable dies which cut out the blank and compress its edges inpractically one operation, although I may use roller-dies to cut andcompress the green-rubber blank in a manner substantially as abovedescribed. After the double-walled edgeseained blank 2 is prepared andcharged with the capsule 12, as above described, it is placed in apreferred form of vulcanizing mold 14 in condition shown in Fig. 5 ofthe drawings, it being understood that the neck portion of the blankhaving intimately-seamed opposite edges4 4: is'eompressed edgewise bythe operators fingers to more easily admit it into the neck-formingportion 15 of the mold. After this mold containing the blank is placedin any approved vulcanizing apparatus the compound 12 will generategases or vapors under pressure which will expand the blank to theshaping-walls of the mold, as indicated in Figs. 6 and 7 of thedrawings, there being usuall y formed at the extremity of the bulb neckor nipple 3 an end wall 16 of rubber compound which is trimmed off afterremoval of the bulb from the mold. Leaving the extremity of theneck-forming portion of the blank 2 unseamed by die-pressure or onlyslightly joined by the cutting of the blank and so as not to form anintegral edging thereat permits said blank-neck portion to be moreeasily compressed edgewise by the operator, as above described, tofacilitate entering it into the mold-cavity 15 and also allows saidblank-neck portion to be more readily expanded by the interior gases orvapors to the walls of said mold-cavity 15 during vulcani- Zation. Thenarrow field of cohesion of the extremity of the blank-neck caused bythe shearing action of the die cut-off 8 offers comparativel y littleresistance to opening into full cylindrical form of the bulb-neck 3 tothe mold-walls 15, as above explained. Fig. 6 of the drawings shows thatthe single surrounding integrally-pressed seam 4. of the green blank 2is quite obliterated during expansion of the bulb during vulcanizationand that where said single intimately-united seam appeared in the blankthere results a simple thickening at 17 of the practically-homogeneouswall of the vulcanized bulb. This thickened portion 17, whileobliterating the one original seam of the blank, materially increasesthe strength of the finished bulb. T he mold preferably has suitableair-vents 18, facilitating the expansion of the blank to its formativewalls.

Hollow rubber articles of any desired size and shape may be produced bymy improved process directly from rubber tubing by the aid of properdies and vulcanizing-molds, and the finished article will havepractically uniform consistency and molecular quality throughout itswalls and will be stronger even if made from lower-grade stock thanarticles of like general character produced from parts stamped fromhighly-calendered sheet-rubber stock and having a number of hand-madejoints or seams, so liable to imperfections,and withindependently-formed plugs inserted to make or reinforce the neck orother prominent part of the article.

It will be specially noticed that in the preferred manner of carryingout my invention I dispense with calendering-machines and expensivecollapsible dies, and I also avoid the expensive and uncertainhand-joining of numerous parts, and I make unnecessary the use of theordinary hollow needle commonly employed to inject a gas or vaporgenerating substance into the hollow green articles for insuring theirinflation in the vulcanizing-Inolds, and I also save largely in the workof trimming the hollow articles to a fi'nal finish for the market. I amtherefore able by my improved process of manufacture to make hollowrubber balls, bulbs, or other articles in great variety at a muchreduced cost, while giving them increased strength and better wearingqualities.

I claim as my invention 1. The herein-described process of making hollowrubber balls, bulbs or other articles, which consists in cutting adouble-walled blank from uncured rubber tubing, then pressing the edgesof said blank-walls into intimate union, and then' vulcanizing theblank, substantially as specified. I

2. The herein-described process of making hollow rubber balls, bulbs orother articles, which consists in placing within uncured rubber tubing agas-generating substance, then cutting from said tubing a doublewalledblank, then pressing the edges of the blankwalls into intimate union andconfining the gasgenerating substance between said walls, and thenvulcanizing the blank, substantially as specified.

3. The herein-described process of making hollow rubber balls, bulbs orother articles,

which consists in diedrawing tubing from rubber stock, cutting adouble-walled blank from said tubing, then pressing the edges of theblank-walls into intimate union, and then vulcanizing the blank,substantially as specified.

4. The herein-described process of making hollow rubber balls, bulbs orother articles, which consists in placing within uncured rubberdie-drawn tubing a gas or vapor generating substance, then cutting adouble-walled blank from said tubing, then pressing the edges of theblank-walls into intimate union and confining the gas-generatingsubstance from said tubing and, simultaneously, in diepressing the edgesof the blank-walls into intimate union and confining the gas-generatingsubstance between said walls, and then vulcanizing the blank,substantially as specified.

7. The herein-described process of making hollow rubber balls, bulbs orother articles, which consists in die-cutting a double-walled blank fromuncured rubber die-drawn tubing and, simultaneously, in die-pressing theedges of the blank-walls into intimate union, and then vulcanizing theblank, substantially as specified.

8. The herein-described process of making hollow rubber balls, bulbs orother articles, which consists in placing within uncured rubberdie-drawn tubing a gas or vapor generating substance, then die-cutting adoublewalled blank from said tubing and, simultaneously, in die-pressingthe edges of the blank-walls into intimate union and confining thegas-generating substance between said -walls, and then vulcanizing theblank, substantially as specified.

9. The here1n-dcscr1bed process of making hollow rubber balls, bulbs orother articles, which consists in cutting a double-walled blank fromuncured rubber tubing, then intimately uniting by pressure the edges ofsaid blank-Walls all around except at the extremity of a neck orprojection forming portion of the blank, and then vulcanizing the blank,substantially as described.

10. The herein-described process of making hollow rubber balls, bulbs orother articles, which consists in placing within uncured rubber tubing agas or Vapor generating substance, thcn cutting a double-walled blankfrom said tubing, then intimately uniting by pressure the edges of saidblank-walls all around except at the end of. a neck or projectionforming portion of the blank and confining the gas-gencrating substancebetween said walls, and then vulcanizing the blank, substantially asspecified.

IRNVIN FLOYD KEPLER.

\Vi tn esses:

WVILLIAM G. BLOOM, HERBERT E. RICHARDSON.

